[PATCH] D33869: [llvm-readobj] More command-line compatibility with GNU readelf

[Roland McGrath via Phabricator via llvm-commits]

mcgrathr created this revision.
Herald added a subscriber: mgorny.

Install an llvm-readelf symlink to llvm-readobj.                            
When invoked as *readelf*, default to -elf-output-style=GNU.

Accept -S as an alias for --sections, as GNU readelf does.

Accept and ignore -W, which in GNU readelf is necessary to produce          
the output format that's consistent between 32-bit and 64-bit               
targets, which is what llvm-readobj always produces.

There are still some incompatibilities with GNU readelf's command           
line option syntax (e.g. -s and -t).  But this makes llvm-readelf           
interchangeable with GNU readelf for more of the common uses,               
e.g. "readelf -W -S -l".


Repository:
  rL LLVM

https://reviews.llvm.org/D33869

Files:
  test/tools/llvm-readobj/gnu-sections.test
  tools/llvm-readobj/CMakeLists.txt
  tools/llvm-readobj/llvm-readobj.cpp


Index: tools/llvm-readobj/llvm-readobj.cpp
===================================================================
--- tools/llvm-readobj/llvm-readobj.cpp
+++ tools/llvm-readobj/llvm-readobj.cpp
@@ -34,6 +34,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/Signals.h"
@@ -50,19 +51,27 @@
     cl::desc("<input object files>"),
     cl::ZeroOrMore);
 
+  // -W
+  cl::opt<bool> IgnoredW("W",
+    cl::desc("Ignored for compatibility with GNU readelf"));
+
   // -file-headers, -h
   cl::opt<bool> FileHeaders("file-headers",
     cl::desc("Display file headers "));
   cl::alias FileHeadersShort("h",
     cl::desc("Alias for --file-headers"),
     cl::aliasopt(FileHeaders));
 
-  // -sections, -s
+  // -sections, -s, -S
+  // Note: In GNU readelf, -s means --symbols!
   cl::opt<bool> Sections("sections",
     cl::desc("Display all sections."));
   cl::alias SectionsShort("s",
     cl::desc("Alias for --sections"),
     cl::aliasopt(Sections));
+  cl::alias SectionsShortUpper("S",
+    cl::desc("Alias for --sections"),
+    cl::aliasopt(Sections));
 
   // -section-relocations, -sr
   cl::opt<bool> SectionRelocations("section-relocations",
@@ -526,13 +535,18 @@
 }
 
 int main(int argc, const char *argv[]) {
-  sys::PrintStackTraceOnErrorSignal(argv[0]);
+  StringRef ToolName = argv[0];
+  sys::PrintStackTraceOnErrorSignal(ToolName);
   PrettyStackTraceProgram X(argc, argv);
   llvm_shutdown_obj Y;
 
   // Register the target printer for --version.
   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
 
+  opts::IgnoredW.setHiddenFlag(cl::Hidden);
+  if (sys::path::stem(ToolName).find("readelf") != StringRef::npos)
+    opts::Output = opts::GNU;
+
   cl::ParseCommandLineOptions(argc, argv, "LLVM Object Reader\n");
 
   // Default to stdin if no filename is specified.
Index: tools/llvm-readobj/CMakeLists.txt
===================================================================
--- tools/llvm-readobj/CMakeLists.txt
+++ tools/llvm-readobj/CMakeLists.txt
@@ -19,3 +19,5 @@
   WasmDumper.cpp
   Win64EHDumper.cpp
   )
+
+add_llvm_tool_symlink(llvm-readelf llvm-readobj)
Index: test/tools/llvm-readobj/gnu-sections.test
===================================================================
--- test/tools/llvm-readobj/gnu-sections.test
+++ test/tools/llvm-readobj/gnu-sections.test
@@ -2,6 +2,8 @@
 RUN:   | FileCheck %s -check-prefix ELF32
 RUN: llvm-readobj -s %p/Inputs/relocs.obj.elf-x86_64 --elf-output-style=GNU \
 RUN:   | FileCheck %s -check-prefix ELF64
+RUN: llvm-readelf -W -S %p/Inputs/relocs.obj.elf-x86_64 \
+RUN:   | FileCheck %s -check-prefix ELF64
 
 ELF32:    Section Headers:
 ELF32-NEXT:      [Nr] Name              Type            Address  Off    Size   ES Flg Lk Inf Al


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